Ingredient review

Benzylidene Camphor Sulfonic Acid

INCI: Benzylidene Camphor Sulfonic Acid

A synthetic UV filter that effectively absorbs UVB and short UVA rays, but its use is restricted in some countries due to environmental concerns.

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In plain English

Benzylidene Camphor Sulfonic Acid is a man-made ingredient added to sunscreens and other products to help block the sun's ultraviolet (UV) rays. It works by absorbing UV light and turning it into harmless heat, preventing it from reaching deeper layers of your skin. You'll find it in some sunscreens, especially those labeled as 'broad spectrum,' but it's not as common as other filters like avobenzone or octinoxate. It's generally considered safe for most people, but it's banned or restricted in some places (like the US) due to concerns about its potential impact on the environment, particularly marine life.

Quick decision guide

Useful, but context matters

Benzylidene Camphor Sulfonic Acid is generally a lower-concern ingredient when the full formula suits your skin.

Plain-English read

Treat this as a practical screening step before you compare products that contain this ingredient.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Benzylidene Camphor Sulfonic Acid.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.

Score terms in plain English

Irritation risk

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

A synthetic organic compound derived from camphor, modified with a benzylidene group and a sulfonic acid group to make it water-soluble and effective as a UV filter.

How it works

It absorbs UVB rays (280–315 nm) and some short UVA rays (up to around 360 nm) through its molecular structure, which converts the UV energy into heat that is then released from the skin. This prevents the UV radiation from damaging skin cells and causing sunburn or long-term skin aging.

Pros

Effective UVB protection

Absorbs UVB rays efficiently, helping prevent sunburn and short-term skin damage.

Water-soluble formulation

Its water solubility allows for lighter, less greasy sunscreen textures that feel comfortable on the skin.

Cons and cautions

Environmental concerns

Studies suggest it may persist in water and harm marine ecosystems, leading to bans in some regions like Hawaii and the US Virgin Islands.

Limited UVA coverage

It only covers short UVA rays, so it's often combined with other filters for broad-spectrum protection, which can complicate formulations.

Best for

  • People looking for a lightweight, water-soluble sunscreen filter
  • Those with oily or combination skin who prefer non-greasy sun protection

Use caution if

  • Individuals concerned about environmental impact or who prefer reef-safe sunscreens
  • Anyone in regions where this ingredient is not approved (e.g., USA) – check local regulations

Usage tips

Apply sunscreen containing this ingredient generously 15 minutes before sun exposure for best protection.
Reapply every two hours, or after swimming or sweating, to maintain effectiveness.

Safety summary

Generally safe for human use at regulated concentrations, with low irritation and allergy risk. However, its environmental impact has led to restrictions in certain areas. For most people, it is a safe and effective UV filter when used as directed.

Research notes

Research confirms its effectiveness as a UVB and short UVA filter. Environmental studies raise concerns about its persistence and ecotoxicity, leading to regulatory restrictions. Human safety data supports its use at approved levels.

Common label clues

Typical concentration
Up to 6% in leave-on products (regulated in many regions)
Regulatory status
Approved as a UV filter in the European Union (up to 6% in leave-on products) and in many other countries, but not approved by the US FDA or in Japan. Banned in some regions due to environmental concerns.
Common uses
Sunscreens, Daily moisturizers with SPF, Cosmetic products requiring UV protection
Environmental note
Studies have detected benzylidene camphor sulfonic acid in water bodies, and it is considered potentially harmful to coral reefs and aquatic life. Some regions have banned it to protect marine ecosystems.

Good to know

  • This ingredient is approved in the EU and many Asian countries but not in the USA or Japan.
  • It is often listed under the name 'Sulisobenzone' in some ingredient databases.

Common questions

What is Benzylidene Camphor Sulfonic Acid in beauty products?

Benzylidene Camphor Sulfonic Acid is a man-made ingredient added to sunscreens and other products to help block the sun's ultraviolet (UV) rays. It works by absorbing UV light and turning it into harmless heat, preventing it from reaching deeper layers of your skin. You'll find it in some sunscreens, especially those labeled as 'broad spectrum,' but it's not as common as other filters like avobenzone or octinoxate. It's generally considered safe for most people, but it's banned or restricted in some places (like the US) due to concerns about its potential impact on the environment, particularly marine life.

What does Benzylidene Camphor Sulfonic Acid do in a beauty product?

It absorbs UVB rays (280–315 nm) and some short UVA rays (up to around 360 nm) through its molecular structure, which converts the UV energy into heat that is then released from the skin. This prevents the UV radiation from damaging skin cells and causing sunburn or long-term skin aging.

Is Benzylidene Camphor Sulfonic Acid safe for most people?

Generally safe for human use at regulated concentrations, with low irritation and allergy risk. However, its environmental impact has led to restrictions in certain areas. For most people, it is a safe and effective UV filter when used as directed.

Who should be careful with Benzylidene Camphor Sulfonic Acid?

Individuals concerned about environmental impact or who prefer reef-safe sunscreens Anyone in regions where this ingredient is not approved (e.g., USA) – check local regulations

Research sources

European Chemicals Agency (ECHA) – Benzylidene Camphor Sulfonic AcidOpenPubChem – Benzylidene Camphor Sulfonic AcidOpenFDA Sunscreen Drug Products for Over-the-Counter Human Use (not approved)Open

Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.